Apparatus and method of removing water soluble support material from a rapid prototype part

ABSTRACT

The support removal apparatus comprising in combination a retention tank having a manifold assembly comprising a plurality of nozzle heads in hydraulic communication with the discharge side of a pump, collectively configured for agitating an aqueous cleaning solution comprised of sodium or potassium hydroxide, sodium or potassium carbonate, and water; a heating element mounted within the retention tank for heating the aqueous cleaning solution to a predetermined temperature set point; a basket strainer mounted within the retention tank in hydraulic communication with the intake side of the pump to mitigate passage of small rapid prototype parts and residual support material therethrough and into the pump and manifold assembly; a work surface mounted atop the retention tank and having a movable lid fitted with a basket for containing small rapid prototype parts; a thermocouple for maintaining the temperature within a tolerable range for optimum removal of support material; a level indicator to ensure adequate solution level in the retention tank for operability of the pump and heating element; a cabinet having interface controller mounted on an exterior panel thereof for setting timer and heat functions; and a microprocessor having capabilities for making minute adjustments to the heating element via feedback from the thermocouple and controlling operation of the pump and heating element for a pre-set time interval.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from U.S. ProvisionalApplication Ser. No. 60/523,776 filed Nov. 19, 2003, entitled “Apparatusand Method of Removing Water Soluble Support Material from a RapidPrototype Part,” the disclosures of which, including all attacheddocuments, are incorporated herein by reference in their entirety forall purposes.

FIELD OF THE INVENTION

The present invention relates in general to an improved apparatus andmethod of removing water soluble support material from a rapid prototypepart. More particularly, the present invention relates to an improvedapparatus comprising means for heating and agitating an aqueous cleaningsolution for accelerated, efficient dissolving of temporary supportmaterial generally utilized in the production of rapid prototype parts.

BACKGROUND OF THE INVENTION

Fused Deposition Modeling (FDM) is one method among a few capable ofdeveloping rapid prototype parts or functional models from athermoplastic material such as ABS (acrylonitrile butadiene styrene) andpolycarbonate. FDM utilizes a computer numeric controlled (CNC)extruder-head which squeezes a fine filament of melted thermoplasticthrough a modeler nozzle. The controller, operating in accord withpre-select, known variables, activates the modeler nozzle to depositheated plastic layer-by-layer to form the desired geometric shape. Insome instances where select features of the part are left unsupported asa result of the part's orientation, the FDM-based machine mayincorporate the use of a second nozzle for extruding therethroughsupport material to create support structures for any cantileveredportions of the part. In cases where the part's build comprises small,intricate features, a water soluble support material may be used tofurther facilitate or ease removal from the part's build uponcompletion. Once the appropriate supporting layer is built,thermoplastic, as discussed above, is extruded through the modelernozzle to form the part's build. Once the part has finished itssuccessive layers and the build is complete, the part is removed fromthe FDM-based machine for inspection and final surface preparation,which may include removal of any support material, additional machining,and/or application of a finish coating material.

In instances where a water soluble support material is used, the artoffers a range of techniques for removing the support material from therapid prototype part. One such technique may simply involve immersingthe part in a suitable solvent repeatedly via manual or automated meansand manually removing the support material using a brush or a pointedtool. Another technique commonly employed in the art may involveplacement within a conventional immersion parts washer of the typegenerally designed to remove grease, carbon, resins, tar, and otherunwanted petroleum-based residuals from automotive parts and machineshop equipment. Typically, the conventional immersion parts washer ofthis type may comprise operable features of ultrasonics to facilitatethe cleansing action of the solvent. Although the operable feature notedabove may or may not adequately address the removal of support material,the conventional immersion parts washer can be costly in terms ofpurchase, maintenance and operation, particularly for this limitedpurpose, and inappropriate in a variety of environmental settings. Giventhat most machinery having rapid prototype part making capabilities isoperated from within an office setting or a similarly suitedenvironment, the coinciding use of a conventional immersion parts washermakes it unacceptable and inappropriate in maintaining a sound, cleanenvironment. Further, some conventional immersion parts washer mayexpose one to unacceptable health risks, particularly those havingultrasonic capabilities (see World Health Organization Report onUltrasound and Ultrasonic Noise, Geneva 1982).

Accordingly, there remains a need for a dedicated apparatus capable ofremoving water soluble support material from a rapid prototype part andoperating side-by-side with a rapid prototype part making machinecommonly placed and operated in an office setting or a similarly suitedenvironment.

BRIEF SUMMARY OF THE INVENTION

In order to overcome the numerous drawbacks apparent in the prior art,an improved support material removal apparatus has been devised for usewith a rapid prototype part making machine, specifically of the typehaving Fused Deposition Modeling (FDM) capabilities.

It is thus an object of the present invention to provide a low cost,non-complicated support material removal apparatus which may be reliablyused in lieu of a conventional immersion parts washer dedicated andknown in the art to remove grease, carbon, resins, tar, and otherunwanted residuals from automotive parts and machine shop equipment.

It is another object of the present invention to provide such a supportmaterial removal apparatus which incorporates means for heating andagitating an aqueous cleaning solution for accelerated, efficientdissolving of support material generally utilized in the production ofrapid prototype parts.

It is another object of the present invention to provide such a supportmaterial removal apparatus which possesses a minimal number of operatingcomponents to ensure sustained, reliable operation throughout itsduration of use.

It is yet another object of the present invention to provide such asupport material removal apparatus which is portable and operableindependent of a rapid prototype part making machine.

It is yet another object of the present invention to provide such asupport material removal apparatus which comprises process controllermeans for setting applicable set points for unattended operation.

It is yet another object of the present invention to provide such asupport material removal apparatus which accommodates a variety of partshapes and sizes to afford versatility and flexibility to the operatorin removing support material from rapid prototype parts and the likehaving unique geometric profiles.

It is yet another object of the present invention to provide such asupport material removal apparatus which can be accommodated within thespatial requirements or foot print of most equipment generally observedand used in an office setting.

It is yet another object of the present invention to provide such asupport material removal apparatus which is readily accessible forpurposes of setup and adjustment and maintenance and repair withoutsustaining substantial operating downtimes.

It is yet another object of the present invention to provide such asupport material removal apparatus which accomplishes the foregoing andother objects and advantages and which is economical, durable, and fullyeffective in performing its intended functions.

In accordance with the present invention, a support material removalapparatus has been devised for use with a rapid prototype part makingmachine, the apparatus comprising in combination a retention tank havinga manifold assembly comprising a plurality of nozzle heads in hydrauliccommunication with the discharge side of a pump, collectively configuredfor agitating an aqueous cleaning solution comprised of sodium orpotassium hydroxide, sodium or potassium carbonate, and water; a heatingelement mounted within the retention tank for heating the aqueouscleaning solution to a predetermined temperature set point; a basketstrainer mounted within the retention tank in hydraulic communicationwith the intake side of the pump to mitigate passage of small rapidprototype parts and residual support material therethrough and into thepump and manifold assembly; a work surface mounted atop the retentiontank and having a movable lid fitted with a basket for containing smallrapid prototype parts; a thermocouple for maintaining the temperaturewithin a tolerable range for optimum removal of support material; alevel indicator to ensure adequate solution level in the retention tankfor operability of the pump and heating element; a cabinet havinginterface controller mounted on an exterior panel thereof for settingtimer and heat functions; and a microprocessor having capabilities formaking minute adjustments to the heating element via feedback from thethermocouple and controlling operation of the pump and heating elementfor a pre-set time interval.

Other objects, features, and advantages of the present invention willbecome apparent in the following detailed description of the preferredembodiments thereof when read in conjunction with the accompanyingdrawings in which like reference numerals depict the same parts in thevarious views.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A preferred embodiment of the present invention will now be described byway of example with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of the preferred embodiment of the presentinvention illustrating a support removal apparatus equipped with abasket;

FIG. 2 is a side cross sectional view of the preferred embodiment of thepresent invention taken on line 2-2 of FIG. 3 illustrating a manifoldassembly and strainer basket situated within an interior chamber;

FIG. 3 is a top view of the preferred embodiment of the presentinvention illustrating a work surface mounted to a retention tank;

FIG. 4 is a side cross sectional view of the preferred embodiment of thepresent invention taken on line 4-4 of FIG. 3 illustrating a strainerbasket and a manifold assembly;

FIG. 5 is a perspective view of the preferred embodiment of the presentinvention illustrating a support removal apparatus equipped with a lid;

FIG. 6 is a side cross sectional view of the preferred embodiment of thepresent invention illustrating an alternative manifold assembly havingan elongate tubular member;

FIG. 7 is a side cross sectional view of the preferred embodiment of thepresent invention illustrating an alternative manifold assembly havingan elongate tubular member connected to an inlet fitting;

FIG. 8 is a partial side cross sectional view of the preferredembodiment of the present invention illustrating an elongate tubularmember connected to a second end of an outlet piping;

FIG. 9 is a flow diagram of the preferred embodiment of the presentinvention illustrating a microprocessor communicatively coupled to athermocouple, pump, heating element, and level indicator;

FIG. 10 is a perspective view of an alternative embodiment of thepresent invention illustrating a retention tank equipped with a boxmanifold;

FIG. 11 is a side cross sectional view of the alternative embodiment ofthe present invention taken on line 11-11 of FIG. 13 illustrating adrain box fitted with an intake side;

FIG. 12 is a side cross sectional view of the alternative embodiment ofthe present invention taken on line 12-12 of FIG. 13 illustrating a boxmanifold and heating element mounted therebelow and encased in a heatchamber;

FIG. 13 is a side elevational view of the alternative embodiment of thepresent invention illustrating a drain box and box manifold mounted to aretention tank;

FIG. 14 is a side cross sectional view of the alternative embodiment ofthe present invention taken on line 14-14 of FIG. 10 illustrating a boxmanifold and a heating element mounted therebelow and a drain boxpositioned across therefrom;

FIG. 15 is a front elevational view of the alternative embodiment of thepresent invention illustrating a box manifold;

FIG. 16 is a side cross sectional view of the alternative embodiment ofthe present invention taken on line 16-16 of FIG. 15 illustrating a boxmanifold;

FIG. 17 is a side cross sectional view of the alternative embodiment ofthe present invention taken on line 17-17 of FIG. 15 illustrating a boxmanifold;

FIG. 18 is a top view of the alternative embodiment of the presentinvention illustrating liquid flows through a retention tank equippedwith a pump and a three-way ball valve;

FIG. 19 is a flow diagram of the alternative embodiment of the presentinvention illustrating a microprocessor communicatively coupled to athermocouple, pump, heating element, level indicator, and athree-position selector switch;

FIG. 20 is a perspective view of the alternative embodiment of thepresent invention illustrating a storage cabinet housing a retentiontank;

FIG. 21 is a perspective view of the alternative embodiment of thepresent invention illustrating a drop basket; and

FIG. 22 is a front elevational view of the alternative embodiment of thepresent invention illustrating a drop box.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While this invention is susceptible of being embodied in many differentforms, the preferred embodiment of the invention is illustrated in theaccompanying drawings and described in detail hereinafter with theunderstanding that the present disclosure is to be considered toexemplify the principles of the present invention and is not intended tolimit the invention to the embodiments illustrated and presented herein.The present invention has particular utility as an apparatus forremoving water soluble supports from a rapid prototype part producedfrom a rapid prototype part making machine such as those thatincorporate Fused Deposition Modeling (FDM) technology.

Referring now to FIGS. 1-5, there is shown generally at 10 a supportremoval apparatus comprising a tank assembly 12 having means for heatingand agitating an aqueous cleaning solution and a cabinet 14 having aninterface controller 16 mounted on an exterior panel 18 thereof fortemporally controlling heat and agitation outputs. The aqueous cleaningsolution most suited for this application comprises a mixture of 25-70weight percent sodium or potassium hydroxide and 5-30 weight percentsodium or potassium carbonate, collectively forming a granular sodium orpotassium composition suitable for mixing with water. Preferably, theaqueous cleaning solution comprises a concentration ratio of 1.05 poundsof granular sodium or potassium composition per one gallon of watersuitably serves in removing water soluble support material from rapidprototype parts within a tolerable temperature range noted hereinafter.

The tank assembly 12, as shown in FIGS. 2 and 3, comprises a retentiontank 20 having four side walls 22 substantially arranged and connectedto one another to form a box-like structure having a bottom leading edge24 fixedly attached to and along the perimeter of a base 26,collectively forming an interior chamber 28 for containing and holdingthe aqueous cleaning solution. In the preferred embodiment, an aperture30 extending through the base primarily serves as means for removingaqueous cleaning solution from the interior chamber for purposes ofrepair and maintenance and like activities. Retention of aqueouscleaning solution in the interior chamber 28 as well as removaltherefrom and through the aperture is principally controlled by a valve32 connected in line to a drain pipe 34 having an input end 36threadably connected to a drain sleeve 38 mounted to and over theaperture at an exterior side 40 of the base and an output end 42terminating at an external waste line or sump collector.

As shown in FIGS. 1 and 2, one side wall 22 of the retention tankpreferably comprises intake and outlet apertures 44, 46 for passage ofintake and outlet piping 48, 50, respectively, each having first ends 48a, 50 a attached to intake and outlet sides 52 a, 52 b of a pump 52mounted exterior to the retention tank and housed within an interiorportion 54 of the cabinet. Pumps most suited for this applicationcomprise of types having centrifugal or magnetic operable means, to namea couple known in the art to possess favorable characteristics tohydraulically convey and circulate aqueous cleaning solution in andthrough the retention tank 20. However, regardless of the pump typeused, pump seals as well as other operable components thereof arepreferably fabricated from materials which are compatible for use in acorrosive, caustic environment given the alkalinity of the aqueouscleaning solution. Accordingly, seals made from ethylene propylene dienemonomer (EPDM) or Viton™ and metallic components made from stainlesssteel tolerably perform well within the predetermined range of operation(temperature and pH) without deleterious impact to pump performance. Asdepicted in FIG. 2, a second end 50 b of the outlet piping 50 isadaptably mounted to a manifold assembly 56 principally serving as meansfor agitating the aqueous cleaning solution contained within theretention tank. Preferably, the manifold assembly is housed within aportion of the interior chamber 28 and comprises at least one nozzlehead 58 threadably mounted to the second end of the outlet piping. In analternative arrangement, one of which utilizes more than one nozzlehead, the manifold assembly comprises a pipe tree fitting 60 having afeed end 62 fixedly attached to the second end 50 b of the outlet pipingand more than one branch ends 64 extending therefrom to evenlydistribute the incoming flow into an equivalent number of nozzle heads58. It is noted herein that the manifold assembly 56 may comprise one ormore in number with each being selectively arranged about the retentiontank 20 to provide for opposing, cross interaction of flows from eachnozzle head, suitably needed in some instances to achieve the desiredlevel of agitation or turbulence within the interior chamber 28. In thisalternative arrangement, the outlet piping is further divided withappropriate fittings commonly available in the art and selectivelyconnected to a predetermined number of pipe tree fittings 60 each havingmultiple branch ends 64 fitted with a nozzle head 58. Each nozzle head,as best illustrated in FIGS. 2 and 4, comprises a nozzle tip 66 and athreaded body 68 threadably mounted to each branch end 64. In order todevelop and continually establish a predominate level of agitationwithin the interior chamber, each nozzle tip is suitably configured withan orifice 70 having a diameter ranging from 0.05 to 0.375″. In thisdiametric range combined with a pump capacity ranging from 3-30 gallonsper minute at a power output ranging {fraction (1/25)}-2 HP, each nozzletip 66 is substantially capable of developing an output pressure rangingfrom 5 to 60 p.s.i., respectively. In this pressure range, each nozzletip provides for a jet stream having a tight dispersion pattern capableof reaching and interacting with and reflecting off the opposing sidewall of the retention tank 20 to uniformly agitate the aqueous cleaningsolution within the interior chamber. In instances where the retentiontank comprises a larger volumetric capacity, more than one manifoldassembly 56, as described above, may be needed to create and maintainhomogenous agitation of the aqueous cleaning solution for sustained andcontinued removal of support material from the rapid prototype part(s).In an alternative embodiment, the manifold assembly in lieu of thenozzle head 58 may comprise of an elongate tubular member 72 having aninlet fitting 74 hydraulically attached and extending perpendicularlythereto and a plurality of orifices 76 being positioned about an outerface 78 thereof, substantially in the manner shown in FIG. 6. Assemblyof the elongate tubular member to the second end 50 b of the outletpiping is accomplished by a sleeve 80 having a first end 82 fixedlyattached thereto and a second end 84 having at least two concentricdepressions 86 for accepting therein an equivalent number of o-rings 88.As illustrated in FIG. 8, a free end 90 of the inlet fitting 74 isslidably positioned onto and over the second end 84 and moved thereaboutuntil the o-rings are completely encased within the inner confines ofthe inlet fitting. Each orifice 76 situated about the outer face 78preferably comprise a wall 92 having a anterior portion 94 a thereofextending perpendicular thereto and a posterior portion 94 b extendingangularly outward a predetermined amount from a midpoint position 94 cin the wall, specifically where the anterior portion terminates withinthe confines of the wall.

As illustrated in FIG. 2, a second end 48 b of the intake piping 48comprises a basket strainer 96 having a plurality of apertures 98extending therethrough for passage of the aqueous cleaning solutionduring cyclic circulation thereof while effectively eliminating thepassage of small rapid prototype part(s) and residual support materialsuspended in solution. A backing plate 100 fixedly attached to thebasket strainer and having a threaded coupling 102 fixedly attachedthereto suitably serves as means for mounting the strainer basket to thesecond end of the intake piping, substantially in the manner shown inFIG. 2. To further mitigate undesirable interaction of small rapidprototype part(s) in suspension with the manifold assembly 56 and basketstrainer, where positive and negative pressure is respectively observed,the retention tank 20 is fitted with a plate guard 104 to divide theinterior chamber 28 into first and second compartments 106, 108. Theplate guard preferably comprises an upper leading edge 110 and aplurality of nozzle apertures 112 extending therethrough to accommodatean equivalent number of nozzle heads 58 for sustained and continuedpassing of the aqueous cleaning solution into the second compartment 108of the interior chamber 28. Mounting of the plate guard within theinterior chamber is substantially accomplished by attaching the upperleading edge 110 to a portion of a work surface 114 suitably situatedabove and attached to the retention tank. All unattached edges of theplate guard are selectively positioned away from the side walls 22 andbase a predetermined distance to form an elongate opening 116therealong, purposefully to maintain circulation of the aqueous cleaningsolution contained within the interior chamber of the retention tank. Toenhance circulation of the aqueous cleaning solution to a greater extentthan that provided by the elongate opening, the plate guard 104 furthercomprises a plurality of openings 104 a collectively positioned near thebottom thereof adjacent to the base 26. Preferably each opening is sizedaccordingly to hinder movement of most rapid prototype part(s) from thesecond compartment into the first compartment, toward the basketstrainer 96, predominately caused by the presence of negative pressurethereat.

To further assist the cleansing action of the aqueous cleaning solutionfor effective removal of support material from rapid prototype part(s),the retention tank is configurably fitted with a heating element 118having an internal end 120 situated within the interior chamber and anexternal end 122 electrically connected to an output line of amicroprocessor 124. As shown in FIG. 4, the heating element is mountedadjacent to the base in the first compartment 106, specifically beingpositioned most near the side wall where the manifold assembly 56 andbasket strainer are located to facilitate distribution of heat to theaqueous cleaning solution via the pump 52 feeding solution into thefirst and second compartments. Although numerous types of heatingelements may be suited for this application, it is preferred that theheating element 118 comprise a power rating ranging from 50-300Watts/sq. in., a power rating of which substantially heats the aqueouscleaning solution to 90-180° F. within a modest time range of at least15-90 minutes, respectively. The heating element may comprise a varietyof geometric configurations and design features such as those having aninternal end selectively shaped as a band, cable, tubular cartridge,strip, to name a few most widely known and available in the art,providing each meets the above operating specifications. It is notedherein that the present invention may alternatively comprise a heatingelement mounted externally to the retention tank in lieu of the heatingelement mounted internally in the interior chamber. In such instance,the retention tank primarily serves as a suitable conductor intransmitting heat to the aqueous cleaning solution. In similar regard interms of substantiating the number of nozzle heads 58, a retention tankcomprising a larger volumetric capacity may necessitate a heatingelement having a higher heatable surface area and output to maintain theoverall effectiveness of the aqueous cleaning solution. Given theoperating characteristics of the aqueous cleaning solution in termsalkalinity, the internal end preferably comprises a sheath fabricatedfrom materials such as stainless steel 304 or 316, Inconel, Incoloy,Monel, or titanium, collectively of the type capable of resistingpremature failure of the heating element during operative conditions.Working in conjunction with the heating element, a thermocouple 126mounted to the retention tank 20 suitably serves as means forcontrolling the temperature of the aqueous cleaning solution within atolerable range noted hereinbefore. As depicted in FIG. 4, thethermocouple comprises an external lead 128 electrically connected tothe input side of the microprocessor 124 and an internal probe 130extending inwardly within the first compartment for which is readilycapable of sensing the ambient temperature of the aqueous cleaningsolution and making timely and minute adjustments to the heating element118 via the microprocessor. Like the heating element in terms ofmaterial choice, the internal end preferably comprises a sheath 132fabricated from or coated with a material most compatible for operationin a corrosive environment. In addition to the available means forheating and agitating the aqueous cleaning solution, a level indicator134 of the type shown in FIG. 4 provides means for activating power tothe microprocessor to permit activation of a timer switch 136 whichcorrespondingly controls the duration of operating the heating elementand pump 52. Further, the level indicator suitably serves as a safetydevice insofar of eliminating premature activation of the pump when theinterior chamber 28 is absent of aqueous cleaning solution. Levelindicators comprising operable features of optics, magnetic, mechanicalmeans, to name a few commonly available in the art, may be suited forthis application providing each comprises means for connectivity to themicroprocessor 124. As illustrated in FIG. 9, the microprocessorselectively controls outputs to the pump and heating element operablybased on time and temperature set points established by the operator ormanufacturer. In the preferred embodiment, a temperature set point ofapproximately 150° F., as set by the manufacturer, establishes optimalperformance of the aqueous cleaning solution. Time input, on the otherhand, is selectively controlled by the user via the interface controller16 comprising means for displaying operating variables of temperatureand time. An example of a suitable microprocessor for this applicationis the type manufactured by the Watlow Company of St. Louis, Mo.,specifically being designated as Watlow Series 935B. It should beunderstood that many other types of microprocessors may be used in thisapplication providing it comprises capabilities to control the desiredoutputs noted above. It is further understood that all electricalcomponents described above, including the pump, heating element,thermocouple, level indicator and microprocessor, may be electricallywired in any known manner. In operation, with reference to FIG. 9, poweris initially supplied to a start switch 137 which subsequently activatesthe level indicator 134. Upon the level indicator detecting the level ofthe aqueous cleaning solution in the retention tank, power is furthertransmitted to the microprocessor at which time the timer is activatedby the operator to set the temporal limits for operating the pump 52 andheating element 118. Process startup is finally achieved by the operatoractivating a controller start button integrally made part of themicroprocessor. It is noted herein that the heating element onlyoperates within a temperature range of approximately 40° F. to the setpoint of 150° F. notwithstanding the time inputs, in contrast to thepump 52 which operates for the full duration of the time input. Uponexpiration of the timer's set limits, power to the pump as well as theheating element is disabled via the microprocessor 124. Reactivation ofthe cleaning cycle substantially involves re-setting the timer functionand activating the controller start button.

As noted above, the retention tank 20 is fitted with a work surface 138of the type comprising a recessed portion 140 having an opening 142extending therethrough, collectively being contained within an upperledge 144 extending along the perimeter of the work surface. The worksurface, particularly the recessed portion, primarily serves incontaining and channeling the aqueous cleaning solution downwardlytoward the retention tank in the event of inadvertent spillage caused bythe removal of rapid prototype parts from the second compartment 108. Asillustrated in FIGS. 1 and 3, the opening preferably comprises ageometric configuration and size substantially conforming to anaccessible opening 146 of the second compartment. To mitigate furtherloss of aqueous cleaning solution, primarily due to evaporation, thework surface further comprises a lid 148 having a geometricconfiguration substantially conforming to the opening 142 of therecessed portion and a handle 150 fixedly attached to an upper surface152 thereof to provide means for removing and placing the lid onto andover the accessible opening 146. In some applications, the lid, as shownin FIG. 1, is adaptably fitted with a basket 154 hanging downwardlytherefrom for holding small rapid prototype parts which easily suspendin solution and readily move about the interior chamber 28. In thisregard, the basket comprises perforated walls 156 substantially arrangedto form an interior portion 157 capable of containing the rapidprototype parts yet permitting the passing of aqueous cleaning solutionupon removal from the retention tank. Preferably, the basket 154comprises an overall geometric configuration substantially capable offitting within the confines of the second compartment 108 and passingunhindered through the opening 142. Access to the basket is madepossible by a parts opening 158 extending through one of its perforatedwalls 156 and when placed within the interior chamber, the parts openingabuts up against the sidewall 22 of the retention tank to impedeoutgoing flow of rapid prototype parts into the interior chamber. Asillustrated in FIGS. 1 and 5, the cabinet 14 further comprises featuresfor operation and maintenance, including an access panel 160 removabletherefrom to gain access to the pump 52 and other operable componentsand, as noted earlier, an interface controller display and the startswitch 137 mounted externally on the cabinet. In most applications, thework surface 138 is welded to the retention tank and collectively placedinto and attached to the cabinet by a plurality of screws.

An alternative embodiment of the present invention is shown in FIGS.10-19. In lieu of the manifold assembly 56 used in the preferredembodiment, the retention tank 20 comprises a large opening 164 toaccommodate a box manifold 166 having a plurality of nozzle heads 58 forenhanced agitation of the aqueous cleaning solution contained within theinterior chamber and a drain box 168 integrally made part thereof forenhanced circulation and removal of aqueous cleaning solution from theretention tank. The box manifold 166 comprises an outer casing 170having an inlet adapter 172 mounted externally thereto and a pressurebox 174 collectively formed by an inner backside 176 of the outer casingas reinforced by an interior reinforcing plate 178 integrally made partof the outer casing and a backing plate 180 used in supporting thenozzle heads 58. As denoted by path E in FIG. 18, the inlet adapter 172is hydraulically connected to an outlet stem 182 of a three-way ballvalve 184. As illustrated in FIGS. 16 and 17, the backing platecomprises a plurality of apertures 186 extending therethrough to receivean equal number of collars 188 each having internal threads 189. Inassembled form, each collar is fixedly attached to the backing plate 180by a bead of weld placed about its outer circumference, with thethreaded body 68 of each nozzle head 58 being threadably connected tothe collar. Similar to the preferred embodiment in terms of protectingthe nozzle head from suspended matter, each nozzle tip 66 is positionedwithin a cavity 190 substantially formed by the backing plate and anozzle plate 192 attached thereto by a plurality of screws 194 and thelike. In order to sustain passing of the aqueous cleaning solution intothe interior chamber, yet mitigating the passage of small rapidprototype parts and residual support material into the box manifold 166,the nozzle plate comprises a plurality of small apertures 196 each beingpositionally aligned with each of the nozzle heads, substantially asillustrated in FIGS. 16 and 17. A gasket 198 situated in between thereinforcing and backing plates mitigates leakage of the pressure box 174and ensures sustained and continuous pressure thereat for passing of theaqueous cleaning solution through the nozzle head 58 and forcibly intothe interior chamber 28.

Referring now to FIGS. 10 and 11, the drain box 168 generally extendsthe full width of the side wall of the retention tank 20 and comprisesan intake side 200 and a bottom 202 coinciding with the base. An outletopening 204 extending through the bottom of the drain box receives anoutlet line 206 extending therefrom and terminating at an intake side208 of the pump, as denoted by path C in FIG. 18. A water input opening210 extending through the bottom 202 suitably receives a fitting 212 forconnecting pipe therefrom to a ball valve 214 primarily serving as meansfor feeding fresh water from an external water source 215 into the drainbox 168 and subsequently into the retention tank 20, as denoted by pathsA and B in FIG. 18. Like the second end of the intake piping, the intakeside 200 is suitably fitted with a screen 216 to inhibit the passage ofsmall rapid prototype parts and residual support material into andthrough the drain box, pump and ball valve, yet affording continuouspassage of the aqueous cleaning solution. Like the preferred embodiment,the retention tank 20 of the alternative embodiment comprises athermocouple 218 having an internal probe 218 a positioned within thedrain box for measuring the ambient temperature of the aqueous cleaningsolution and controlling heat inputs to the microprocessor and a heatingelement 220 having an internal end 220 a of the band type suitablysituated near the base and housed in a heat chamber 221 substantiallyextending about the width of the side wall 22 and placed opposite to thelocation of the drain box 168, below the box manifold, and an externalend 220 b communicatively coupled to the microprocessor 124. A screen221 a similar to the one attached on the intake side of the drain box ismounted to an elongate opening 221 b of the heat chamber. The retentiontank of the alternative embodiment further comprises a level indicator222 to the likes discussed for use with the preferred embodiment,particularly of the type substantially capable of measuring the level ofthe aqueous cleaning solution within the interior chamber 28 to ensureinoperative status of the pump 52 in the event that the solution levelis inadequate to support flow through the pump and box manifold andfurther ensure that each nozzle head is situated below the solutionlevel. As respectively denoted by paths D and F in FIG. 18, thethree-way ball valve 184 further comprises an intake stem 224hydraulically connected to a discharge side 226 of the pump and a drainstem 228 a hydraulically connected to an external drain line 228 b,which collectively serve in circulating and removing the aqueouscleaning solution in and from the interior chamber 28. Althoughoperation of the alternative embodiment is substantially similar to thepreferred embodiment in terms of controlling temperature, flow and timefunctions, the alternative embodiment further comprises a three-positionselector switch 229 having operable modes designated as off, cleanparts, and drain tank, as best illustrated in FIG. 19. In the cleanparts mode, the alternative embodiment functions similarly to thepreferred embodiment with exception that the user can locally operatethe incoming water supply by manually turning a handle 230 made part ofthe ball valve 214 in the direction of flow, after which the tank fillswith the aqueous cleaning solution to a predetermined level. Time inputsare subsequently entered into the microprocessor 124 via the interfacecontroller and the controller start button is activated to power theheating element and pump for a set duration of time. The drain modeprimarily serves as means for bypassing the microprocessor 124 insofarto simultaneously activate the pump 58 and a magnetic switch 231 madeintegrally part of the three-way ball valve to direct flow outwardlyfrom the retention tank via path F in FIG. 18.

Like the preferred embodiment of the present invention, the alternativeembodiment can be fitted with a work surface 138 having recessedfeatures and means to mitigate evaporative loss of the aqueous cleaningsolution during operation. Further, the alternative embodiment can behoused in a cabinet 14 to the likes described for the preferredembodiment. Alternatively, as shown in FIG. 20, the preferred andalternative embodiments may be suitably housed in a storage cabinet 232having accessible storage capacity 234, an integral work platform 236and a localized water source 238 and drain hydraulically connected to anexternal water supply and drain line, respectively. In thisconfiguration, the retention tank 20 comprises a mounting flange 240extending outwardly from and along an upper perimeter 242 integrallymade part thereof, which substantially serves as means for securing andattaching the retention tank to the integral work platform of thestorage cabinet. In mitigating evaporative loss to the likes of thecabinet used for the preferred embodiment, the storage cabinet 232preferably comprises a cover 244 having a hinge 246 mounted along itsback leading edge and a handle 248 attached to an exterior surface 250thereof. A backstop 252 fixedly mounted to the work platform 236suitably serves in controlling the extent to which the cover movesbeyond the location of the cover's hinge and provides means formaintaining the vertical orientation of a drop basket 254 alternativelymade part of the cover, particularly of the type shown in FIG. 21. Apair of sliding brackets 256 each having a movable slide bar 258 toengage an opening 260 extending through an end wall of the back stopserves as means for locking the cover to the back top 252 in asubstantial vertical orientation. The drop basket 254, as shown in FIGS.21 and 22, comprises an overall rectangular configuration having a toplid 262 hingedly attached to one corner thereof and secured in place bya frontal latch 264 engaging a s-shaped member 266 mounted to a frontside 268 of the drop basket. A pair of handles 270 mounted to anexterior surface 272 of the top lid 262 serves as means for lifting andlowering the top lid from and to the drop basket 254. Mounting of thedrop basket to the cover 244 is primarily accomplished by upwardly anddownwardly orientated lip brackets 274 a, 274 b configured in such amanner to slidably engage and lock with one another. As shownspecifically in FIG. 22, the upwardly orientated lip bracket is attachedto a backside of the cover 244 and engages the downwardly orientated lipbracket as attached to a backside of the drop basket.

It can be seen from the foregoing that there is provided in accordancewith this invention a simple and easily operated device, which isparticularly suited to operate side-by-side with a rapid prototype partsmaking machine in an office setting or similarly suited environment. Thesupport removal apparatus 10 is completely functional in removing watersoluble supports most efficiently from rapid prototype parts givenoptimum operability in terms of aqueous cleaning solution type andconcentration, agitation, and temperature.

It is obvious that the components comprising the support removalapparatus may be fabricated from a variety of materials, providing suchselection or use of materials possess the capacity to withstandpremature corrosion given the presence and use of an alkaline aqueouscleaning solution, notably falling within an applicable pH range of8-11. Accordingly, it is most desirable, and therefore preferred, toconstruct the retention tank 20, work surface 138, lid 148 and nozzleheads 58 from 316 stainless steel; pipe and fittings from a polymericmaterial such as polyamide (PA) or acrylonitrile-butadiene-styrene(ABS); and cabinet 14 and storage cabinet 232 from a lower gradestainless steel. It is noted herein that the retention tank, nozzlehead, work surface, and integral work platform may be alternativelyfabricated from materials to lessen the overall weight of the supportremoval apparatus yet maintaining sufficient resistance to corrosion,such as polypropylene, polyoxymethylene, polyphenylene, ABS, or PA.Similarly, the pump, thermocouple, heating element, and level indictor,particularly exposed operable components of each, are fabricated from ahigh grade stainless steel (316) or coated with an impervious,corrosive-resistant material such as epoxy.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that variouschanges and alterations can be made therein without departing from theinvention and, therefore, it is aimed in the appended claims to coverall such changes and alterations which fall within the true spirit andscope of the invention.

1. An apparatus for removing water soluble support material from a rapidprototype part, said apparatus comprising in combination: a retentiontank having walls and a base collectively forming an interior chamberfor containing and storing an aqueous cleaning solution; means forremoving the aqueous cleaning solution from said interior chamber formaintenance and repair purposes; means for agitating the aqueouscleaning solution contained within said interior chamber; means forheating the aqueous cleaning solution contained within said interiorchamber to a predetermined temperature range; a thermocouple having aninternal probe positioned internally in said interior chamber to engagethe aqueous cleaning solution and an external lead coupled to amicroprocessor for measuring temperature of the aqueous cleaningsolution; and a level indicator positioned internally in said interiorchamber at a predetermined distance above said agitating means fortransmitting level measurements of the aqueous cleaning solution presentin said interior chamber to said microprocessor to activate said heatingmeans and agitating means for a predetermined time interval asprincipally established and controlled by a timer.
 2. An apparatus asset forth in claim 1, wherein said removing means comprises an apertureextending through said base and adaptably fitted with a valve forselectively controlling flow of the aqueous cleaning solution from saidinterior chamber into an external sump collector.
 3. An apparatus as setforth in claim 1, wherein said agitating means comprises intake andoutlet piping passing through intake and outlet apertures extendingthrough said wall of retention tank, said intake and outlet piping eachhaving one end attached to intake and outlet sides of a pump and asecond end attached to a basket strainer and a manifold assembly,respectively.
 4. An apparatus as set forth in claim 3, wherein saidmanifold assembly comprises a nozzle head having a nozzle tip and athreaded body threadably attached to said second end of outlet piping.5. An apparatus as set forth in claim 3, wherein said manifold assemblycomprises a pipe tree fitting having a feed end fixedly attached to saidsecond end of outlet piping and more than one branch ends extendingoutwardly therefrom each being threadably fitted with a nozzle headhaving a nozzle tip for passing therethrough the aqueous cleaningsolution.
 6. An apparatus as set forth in claim 3, wherein said manifoldassembly comprises an elongate tubular member having a plurality oforifices positioned about an outer face thereof and an inlet fittinghaving a free end slidably positioned over a second end of a sleeve withthe first end thereof being fixedly attached to said second end ofoutlet piping.
 7. An apparatus as set forth in claim 6, wherein saidsecond end of sleeve comprises at least two concentric depressions foraccepting therein an equivalent number of O-rings for tighteninglyholding and sealing together said free end of inlet fitting and saidsecond end of sleeve.
 8. An apparatus as set forth in claim 6, whereineach of said orifices comprises a wall having an anterior portionextending perpendicular to said outer face and a posterior portionextending angularly outward a predetermined amount from a midpointposition in said wall.
 9. An apparatus as set forth in claim 1, whereinthe aqueous cleaning solution comprises a granular sodium compositionmixed with water.
 10. An apparatus as set forth in claim 9, wherein thegranular sodium composition comprises a mixture of 25-70 weight percentsodium hydroxide and 5-30 weight percent sodium carbonate.
 11. Anapparatus as set forth in claim 1, wherein the aqueous cleaning solutioncomprises a concentration ratio of 1.05 pounds of granular sodiumcomposition per one gallon of water.
 12. An apparatus as set forth inclaim 1, wherein the aqueous cleaning solution comprises a granularpotassium composition mixed with water.
 13. An apparatus as set forth inclaim 12, wherein the granular potassium composition comprises a mixtureof 25-70 weight percent potassium hydroxide and 5-30 weight percentpotassium carbonate.
 14. An apparatus as set forth in claim 1, whereinthe aqueous cleaning solution comprises a concentration ratio of 1.05pounds of granular potassium composition per one gallon of water.
 15. Anapparatus as set forth in claim 1, wherein said heating means comprisesa heating element having an internal end positioned internally in saidinterior chamber to engage the aqueous cleaning solution and an externalend communicatively coupled to said microprocessor for controlling heatinput to the aqueous cleaning solution contained within said interiorchamber.
 16. An apparatus as set forth in claim 15, wherein said heatingelement comprises a power rating ranging from 50-300 Watts per squareinch.
 17. An apparatus as set forth in claim 1, wherein said retentiontank is fabricated from stainless steel having conductive andcorrosive-resisting properties.
 18. An apparatus as set forth in claim17, wherein said heating means comprises a heating element having anexternal end communicatively coupled to said microprocessor and aninternal end mounted externally on and engaging said wall of retentiontank for indirect transmission of heat to the aqueous cleaning solutioncontained within said interior chamber.
 19. An apparatus as set forth inclaim 1, further comprising a plate guard having an upper leading edgeattached to said retention tank to divide said interior chamber intofirst and second compartments and a plurality of openings extendingtherethrough to accommodate passage of the aqueous cleaning solutioninto and from said first and second compartments while simultaneouslyinhibiting the passage of rapid prototype parts into said firstcompartment and preventing interference with said agitating means and aplurality of nozzle apertures selectively arranged to permit flow beyondsaid plate guard and into said second compartment.
 20. An apparatus asset forth in claim 19, wherein said plate guard comprises a geometricconfiguration to form an elongate opening in between said walls and baseof retention tank to accommodate further passage of the aqueous cleaningsolution into and from said first and second compartments whilesimultaneously inhibiting the passage of rapid prototype parts into saidfirst compartment.
 21. An apparatus as set forth in claim 1, furthercomprising a work surface mounted to said retention tank and having arecessed portion and an opening fitted therewithin for containing andchanneling the aqueous cleaning solution back into said interiorchamber.
 22. An apparatus as set forth in claim 21, wherein said worksurface further comprises a lid having a geometric configurationsubstantially conforming to said opening and a handle affixed to anupper surface thereof to serve as means for handling said lid duringoperation.
 23. An apparatus as set forth in claim 22, wherein said lidfurther comprises a basket hanging downwardly therefrom and havingperforated walls to permit passage of the aqueous cleaning solutionwhile simultaneously inhibiting the passage of rapid prototype parts anda parts opening extending through one of its perforated walls to permitaccess to an interior portion thereof, said basket further comprising anoverall geometric configuration substantially capable of fitting throughthe confines of said opening for positioning within said interiorchamber.
 24. An apparatus as set forth in claim 23, wherein saidretention tank, agitating means, heating means, and microprocessor arecollectively housed within a cabinet having an exterior panel formounting thereon an interface controller and a start switchcommunicatively coupled to said microprocessor and an access panel forgaining access to said agitating means, heating means, andmicroprocessor for repair and maintenance.
 25. An apparatus as set forthin claim 1, wherein said heating means is activated for a temperaturerange of approximately 40° F. to a set point of 150° F.
 26. An apparatusfor removing water soluble support material from a rapid prototype part,said apparatus comprising in combination: a retention tank having wallsand a base collectively forming an interior chamber for containing andstoring an aqueous cleaning solution; a drain box substantiallypositioned about the length of said wall of retention tank and having abottom coinciding with said base of retention tank and an intake side inhydraulic communication with said interior chamber, said drain boxfurther comprising a water input opening hydraulically connected to anexternal water source for supplying fresh water into said interiorchamber as selectively controlled by a ball valve; a box manifold havingan outer casing fitted with an inlet adapter and a pressure boxcollectively formed by an inner backside of said outer casing, aninterior reinforcing plate integrally made part of said outer casing,and a backing plate for mounting a plurality of collars each havinginternal threads for threadably receiving a threaded body of a nozzlehead, said box manifold being mounted over a large opening extendingthrough said wall of retention tank and orientated to permit the passageof aqueous cleaning solution through a nozzle tip of said nozzle headinto said interior chamber; means for conveying the aqueous cleaningsolution in and through said drain box and said box manifold; means forremoving aqueous cleaning solution from said interior chamber; a heatingelement having an external end communicatively coupled to amicroprocessor and an internal end housed within a heat chamber havingan elongate opening in hydraulic communication with said interiorchamber and substantially positioned about the length of said wall ofretention tank and placed across from said drain box, adjacent to andbelow said box manifold; a thermocouple having an internal probepositioned internally in said drain box to engage the aqueous cleaningsolution and an external lead communicatively coupled to saidmicroprocessor for measuring temperature of the aqueous cleaningsolution; and a level indicator positioned internally in said interiorchamber at a predetermined distance above said box manifold fortransmitting level measurements of the aqueous cleaning solution presentin said interior chamber to said microprocessor to activate said heatingmeans and agitating means for a predetermined time interval asprincipally established and controlled by a timer.
 27. An apparatus asset forth in claim 26, wherein said conveying means comprises a pumphaving an intake side hydraulically coupled to an outlet openingextending through said bottom of drain box and a discharge sidehydraulically coupled to an intake stem of a three-way ball valve, saidinlet adapter of outer casing being hydraulically coupled to an outletstem of said three-way ball valve.
 28. An apparatus as set forth inclaim 27, wherein said retention tank, pump, three-way ball valve, andmicroprocessor are collectively housed within a storage cabinet havingaccessible storage capacity, an integral work platform, and a localizedwater source and drain hydraulically coupled to an external water supplyand drain line, respectively.
 29. An apparatus as set forth in claim 28,wherein said retention tank comprises a mounting flange for attachmentto said integral work platform, said storage cabinet further comprisinga cover for covering said interior chamber to mitigate evaporativelosses therefrom and having a hinge mounted along a back leading edgethereof, a handle mounted to an exterior surface thereof for handlingsaid cover during operation, and a backstop for limiting and holdingsaid cover at a predetermined angular position above said interiorchamber.
 30. An apparatus as set forth in claim 29, wherein said covercomprises an upwardly orientated lip bracket for supporting and holdinga drop basket having a downwardly orientated lip bracket attached to abackside thereof to slidably accept and engage with said upwardlyorientated lip bracket, said drop basket comprising a top lid hingedlyattached to a corner thereof and secured thereat by a frontal latchengaging a s-shaped member mounted to a front side of said drop basketand having a pair of handles mounted on an exterior surface thereof. 31.An apparatus as set forth in claim 30, wherein said cover furthercomprises a pair of sliding brackets each having a movable slide bar toengage an opening extending through an end wall of said backstop to locksaid cover to said backstop in a substantial vertical orientation. 32.An apparatus as set forth in claim 26, wherein said removing meanscomprises an external drain line hydraulically coupled to a drain stemof a three-way ball valve.
 33. An apparatus as set forth in claim 26,wherein said box manifold further comprises a nozzle plate mounted tosaid backing plate to form a cavity for housing therein said nozzle tipand having a plurality of small apertures each extending therethroughand being positioned in alignment with said nozzle tip to permitunhindered passage of the aqueous cleaning solution into said interiorchamber.
 34. An apparatus as set forth in claim 26, further comprising agasket positioned in between said interior reinforcing plate and backingplate to mitigate leakage of said pressure box to permit sustained andcontinued pressure therein for forcibly passing the aqueous cleaningsolution through said nozzle head and into said interior chamber.
 35. Anapparatus as set forth in claim 26, wherein the aqueous cleaningsolution comprises a granular sodium composition mixed with water. 36.An apparatus as set forth in claim 35, wherein the granular sodiumcomposition comprises a mixture of 25-70 weight percent sodium hydroxideand 5-30 weight percent sodium carbonate.
 37. An apparatus as set forthin claim 26, wherein the aqueous cleaning solution comprises aconcentration ratio of 1.05 pounds of granular sodium composition perone gallon of water.
 38. An apparatus as set forth in claim 26, whereinthe aqueous cleaning solution comprises a granular potassium compositionmixed with water.
 39. An apparatus as set forth in claim 38, wherein thegranular potassium composition comprises a mixture of 25-70 weightpercent potassium hydroxide and 5-30 weight percent potassium carbonate.40. An apparatus as set forth in claim 26, wherein the aqueous cleaningsolution comprises a concentration ratio of 1.05 pounds of granularpotassium composition per one gallon of water.
 41. An apparatus as setforth in claim 26, further comprising a three-position selector switchcommunicatively coupled to said microprocessor and having operable modesdesignated as off, clean parts, and drain tank.
 42. A method of removingwater soluble support material from a rapid prototype part, said methodcomprising the steps of: configuring and connecting together walls and abase to form an interior chamber for containing and storing an aqueouscleaning solution; mounting a drain box along the length of said walland configuring said drain box to permit a bottom thereof to coincidewith said base and an intake side thereof to hydraulically communicatewith said interior chamber, said drain box comprising a water inputopening hydraulically connected to an external water source forsupplying fresh water into said interior chamber as selectivelycontrolled by a ball valve mounted externally to said interior chamber;attaching a box manifold over a large opening extending through saidwall, said box manifold having an outer casing fitted with an inletadapter and a pressure box collectively formed by an inner backside ofsaid outer casing, an interior reinforcing plate integrally made part ofsaid outer casing, and a backing plate for mounting a plurality ofcollars each having internal threads for threadably receiving a threadedbody of a nozzle head; measuring the level of the aqueous cleaningsolution with a level indicator positioned internally in said interiorchamber at a predetermined distance above said box manifold andtransmitting level measurements to a microprocessor to permit activationof a heating element and a pump for a predetermined time interval asprincipally established and controlled by a timer; heating the aqueouscleaning solution to a predetermined temperature range with said heatingelement having an external end communicatively coupled to saidmicroprocessor and an internal end housed within a heat chamber havingan elongate opening in hydraulic communication with said interiorchamber and substantially positioned to extend the length of said walland orientated across from said drain box, adjacent to and below saidbox manifold; conveying the aqueous cleaning solution in and throughsaid drain box and said box manifold with said pump having an intakeside hydraulically coupled to an outlet opening extending through saidbottom of drain box and a discharge side hydraulically coupled to anintake stem of a three-way ball valve, said inlet adapter of outercasing being hydraulically coupled to an outlet stem of said three-wayball valve; and measuring the temperature of the aqueous cleaningsolution present in said interior chamber with a thermocouple having aninternal probe positioned internally in said drain box to engage theaqueous cleaning solution and an external lead coupled to saidmicroprocessor.
 43. A method as set forth in claim 42, wherein theaqueous cleaning solution comprises a granular sodium composition mixedwith water.
 44. A method as set forth in claim 42, wherein the aqueouscleaning solution comprises a granular potassium composition mixed withwater.
 45. A method as set forth in claim 42, further comprising thestep of removing the aqueous cleaning solution from said interiorchamber for purposes of repair and maintenance with an external drainline hydraulically coupled to a drain stem of said three-way ball valveand activating a three-position selector switch communicatively coupledto said microprocessor and selecting an operable mode configuredtherefor to drain tank for activation of a magnetic switchcommunicatively coupled to said pump.